You can’t Google the words “baby sleep” without being inundated with a barrage of sleep training ads and methods, all claiming to do it gentlest, fastest, and best. But, what does the science and the research actually show about how effective and healthy sleep training is for our infants and young children?

I’m am thrilled to have neuroscientist, doula and the author of the book The Nurture Revolution: Grow Your Baby’s Brain and Transform Their Mental Health through the Art of Nurtured Parenting Dr. Greer Kirshenbaum back on the podcast to talk about the science of sleep!

We’re not going to tell you what you should or shouldn’t do, but instead our goal is to arm you with all the information you need so that you are able to make informed decisions about what is best for you and your unique family – with no shame, judgment, pressure, or fear!

Dr. Greer (00:00:00):

In sleep, that’s where their brain is building. That’s where the circuits are building. They’re consolidating all their information and while they have the safety signals of their caregivers during sleep, when they can smell, you touch you. All of these things, babies sleep longer because they’re not experiencing this higher level of stress.

Dr. Sarah (00:00:29):

It is impossible to Google the words “baby sleep” without being completely inundated with a barrage of sleep training ads and methods, all claiming to do a gentlest fastest best. But what does the science and the research actually show about effective and healthy sleep training and how it impacts our children, our infants and parents? I am so thrilled to have neuroscientist, doula and the author of the book, The Nurture Revolution: Grow Your Baby’s Brain and Transform Their Mental Health Through the Art of Nurtured Parenting, Dr. Greer Kirshenbaum back on the podcast to talk about the science of sleep. We are not, I repeat. We are not going to tell you what you should or shouldn’t do. Our goal in this episode is only to equip you with all the information that you need to have so that you are able to make informed decisions about what is best for you and your unique family with no shame, no judgment, no pressure, and no fear. I hope that that is helpful.


Hi, I’m Dr. Sarah Bren, a clinical psychologist and mom of two. In this podcast, I’ve taken all of my clinical experience, current research on brain science and child psychology and the insights I’ve gained on my own parenting journey and distilled everything down into easy to understand and actionable parenting insights so you can tune out the noise and tune into your own authentic parenting voice with confidence and calm. This is Securely Attached.


Hey everyone. You are going to recognize my guest. If you have listened to our previous episode, I am thrilled because Dr. Greer Kirshenbaum is back today to talk about the neuroscience of sleep and sleep learning and sleep training and all the things. And I’m so glad you’re here. Thanks for coming.

Dr. Greer (00:02:47):

Thank you. Thank you so much. I always get both nervous and excited to dive into infant sleep because it’s a very emotional and passionate subject of mine and of parents. It’s a heated topic for lots of reasons.

Dr. Sarah (00:03:06):

It is, and I feel the same way. I feel nervous and excited because one, as a parent who has two kids who definitely values my sleep and their sleep, I am interested in learning ways to support it that benefit me, that help me. I love my kids. I want them to be healthy and happy and securely attached. And I also really want to sleep. But also as a person who works with parents, I know that it is not simple. It is not black and white. Good, bad. It’s complicated and I feel like you are a very, very good person to have come on because we can talk about the data, the science, the information, but we could talk about it in a way that does not put parents in a position where they have to pick something that they’re backed into a corner. And this is like I want parents to, like you were just saying before we hit record, have the capacity for making an informed choice, but it’s still a choice.

Dr. Greer (00:04:12):

Yes. And I think parents, the way it stands now don’t usually have informed choice. I think right now sleep training seems to be the only choice or the only route to go for lots of families where they think, whether they feel comfortable with it or not. That message is out there so strongly and that’s changing a little bit, but mostly out there so strongly that it’s the only way to handle infant sleep, the only way that sleep will ever develop in a healthy way, the only way that parents can maintain their sanity. It’s absolutely necessary. It may be hard, but it’s necessary. And there’s a lot of parents who might not make that choice if they were given informed choice with sleep. So to clear it up right now to say there’s a lot of choices to make that use different sleep training methods and there’s a lot of choices to make to support infant sleep as it develops, and that allows relief for a lot of people.

Dr. Sarah (00:05:20):

Yes. And I’ll add too, I think, and we’ll talk about this I’m sure, but one, I think we have to define sleep training because there’s a million, it’s one of those words or phrases now that’s kicked around so much that we actually have no idea what anyone’s talking about when they say sleep training because there’s an infinite number ways now to approach it and we all label it the same thing. And so that’s very confusing. So I think that’s really important to talk about what we’re talking about when we say sleep training. But the other thing that I think is very important is we’re talking a little bit about infant, but I also think a lot of what we’re talking about can be applied to toddler and older kids’ sleep and importantly, so because I think a lot of parents who are listening to this may not have a brand new baby. If you do, you are in the right place. You are going to be set up for a success right now. But if you have a older kid and you’ve already done sleep training, you might sit here being like, oh my god, and I don’t want parents to do that. You’re going to make sure you not feel that way by the end of this episode because that’s not the point of this.

Dr. Greer (00:06:27):

Absolutely. And I think it’s really important to normalize as well, whether sleep training is done or not, that babies, toddlers and children, many do need support at night and support with sleep. And I think a lot of parents can feel shame if their children do need that, right? Something’s wrong with me, something’s wrong with my child, something’s wrong with their sleep. And so going over some of the expected sleep physiology of babies and children can also be really helpful for parents to know that supporting it, listening to what their child needs at night. That’s great and really beneficial too, regardless of their age.

Dr. Sarah (00:07:10):

Yes. Okay, so then let’s start there. Let’s start with the physiology and the neuroscience piece because you do an incredible job explaining this. And by the way, your book, The Nurture Revolution, is a great resource for all of this stuff. So I’ll link that book in the show notes, but that’s really a great resource. But can you lay out what we know?

Dr. Greer (00:07:34):

And when I talk about infant sleep, it’s zero to three years old, so that does include babies and toddlers. But what many of us would talk about, and their sleep is very different than adult sleep. I think a lot of times in our culture it’s expected, okay, by the time baby’s four months or six months old time for them to sleep like an adult. And that is just not what their brain and body is going to do. It’s really important to say as well, before we talk about what’s typical for infant sleep, there’s a huge range, huge, huge, huge range of what is normal in terms of number of hours that babies sleep over 24 hours, the number of naps, the length of naps, and so any of those resources out there telling you how many hours your baby needs to sleep overnight. And for naps, we don’t disregard them, your baby, when we set them up with the right conditions for sleep, their body and brain will take the sleep. It needs to go through different sleep cycles to learn, grow, and thrive, and it can’t come from an outside source. It’s this huge, huge variation. So that’s hard because it’s huge. And some babies, the sleep tons in every 24 hours and other babies relatively sleep very little in 24 hours. And the amount of care and demands on parents is also going to vary quite a bit. So I think a lot of the normal features of infant sleep are labeled as problems.

Dr. Sarah (00:09:17):

Interesting. Yes.

Dr. Greer (00:09:18):

Which is really hard for parents because then they’re like, oh my gosh, my baby has all these problems. And actually a lot of them are normal. So you firstly, night waking, biggest one, the biggest one, babies have shorter sleep cycles than us as adults. Their sleep cycles are 45 to 60 minutes. Ours as adults are about 90 minutes. And so every time anybody sleeps after every sleep cycle, we briefly go into a very light sleep or almost a waking state. As adults, we don’t remember. But babies, every time they go through a sleep cycle is an opportunity for them to do a check from head to toe, am I hungry, thirsty, uncomfortable, lonely, all the things. And they can have needs at night. They can need a feed, some water or milk, hydration, cuddling, closeness, and to know they’re safe, right? They’re always looking out, am I safe? Is somebody here for me? So the night waking actually is very normal. In babies, it can be an issue. If it’s extremely frequent, then there’s likely an underlying source of that. There’s a lot of medical issues that could be underlying it. But if a baby is waking every few hours in the first year and then after that they can sleep a bit longer, that is normal and expected actually for many babies. And that’s a huge problem for labeled as a big problem.

Dr. Sarah (00:11:08):

And it could feel like a problem. There’s two folds, there’s the actual real problem that it creates, which is parent sleep deprivation. But then there’s the other sort of societal and maybe perhaps in projected quote problem that maybe we have to reframe, which is there’s something wrong with my child’s sleep or there’s something wrong with their ability to develop into a good sleeper because of these wakings. And that I think is the false interpretation. I do think parent sleep deprivation is a legitimate problem. It just may not be one that is easily solved for in this period of time.

Dr. Greer (00:11:49):

For sure. And I think I work with so many families, I think we can always a place where parents are tired because parents with and without sleep training are tired. Every parent is tired but not sleep deprived. There’s a lot of ways we can set up sleep environments and set up support. Hopefully there’s two parents, if there’s one parent bringing in other people, it’s not, again, not a thing meant to be done by one or two people.

Dr. Sarah (00:12:17):

And unfortunately from a species, it’s not meant to be done by one or two people. But in our society, there are systems that have been set up that may be forcing people to do this all by themselves. Even. I mean, in an ideal situation, you’ve got at least two, but very many people have to do this by themselves, even if they have a partner, which we could talk about too.

Dr. Greer (00:12:41):

100%. Many, many, many people. A hundred percent. Yeah. So yeah, the night waking is a normal feature of infant sleep. Night waking happens with and without sleep training. Most studies on sleep training are parent report. And so after a sleep training protocol, parents report that baby sleep is better because the baby is not signaling for them anymore at nighttime. But when we look at newer studies, there’s three in particular I looked at this morning to refresh myself. We are videoing babies and actually observing them and after sleep training, their night waking doesn’t change. They’re still waking up the same amount. Two of the studies showed that there’s about 15 to 20 minutes extra sleep in total when babies are sleep trained versus not sleep trained. But then generally it’s not significantly increasing the amount they’re sleeping and is not changing these night wakings. It is a feature of their sleep that remains no matter what. So if people are motivated to sleep, train for that reason, oh my baby, I have to do it to shape their sleep, I have to change how they sleep with this. That is actually not happening through sleep training.

Dr. Sarah (00:14:06):

Very interesting and very important because I think, again, people have different reasons for choosing to do this, but many of them are, like you said, it’s informed choice and parents are not making an informed choice if the reason they’re doing something is based on misinformation. So if you are believing and being told to believe and lots of sources are communicating to you, sleep training lengthens the amount of time babies sleep significantly, what we’re finding is that is not in fact true 15 minutes perhaps, but in the grand scheme of things, that is not changing the amount of time they’re sleeping. It’s changing what?

Dr. Greer (00:14:49):

It’s changing their behavior to signal when they wake.

Dr. Sarah (00:14:56):

Okay. Can you talk a little bit about the function of that behavior? Why do babies signal when they wake?

Dr. Greer (00:15:04):

Yeah, absolutely. So anytime babies are signaling, they are communicating needs to us. And so there could be so many, there’s so many needs. Listen to my last episode. We talk a lot about the stress system and how the stress system is developing in babies. And if a baby is signaling a cry or any sort of communication within that kind of sphere of sadness, fear, anger, anything like that, their amygdala is going off, they’re sensing a threat either in their environment or an internal threat. And so internal threats could be, I’m hungry, I’m thirsty, I’m cold, I’m hot, my tags are itchy in my clothes. Those are real life or threats for a baby’s brain. It’s like something’s disrupting my homeostasis. I need help getting back.

Dr. Sarah (00:16:10):

Yes, perceived threats, very real perceived life or death threats because their sense of perception is amplified. Importantly, I think I don’t want parents to be like, oh my God, my baby being hungry at night is life or death. Your baby perceiving hunger cues at night makes their amygdala think it’s life or death, and that is why they’re having a sort of life or death level reaction. And I think how we respond to that is very important in what we were talking about in our last step is shaping this sort of neural circuitry around threat. When the amygdala signals this threat response inside of my body and I freak out and my parent comes in kind of freaking out at me with me, it’s kind of coating and reinforcing that amygdala response. Whereas if we come in, come in, if we come in calmly, slowly regulated, we reflect back to them what’s happening, we mark it a little bit marking meaning like we down regulated like, oh yes, you’re upset. I see that we’re meeting them and then bringing it back down. That’s informing the way the amygdala is now encoding that threat. Oh, when I have that wake up and I feel that hunger and I, it might have to be multiple, multiple iterations of this, but if we do it a bunch of times, then amygdala is going to start to say, okay, when I wake up and I feel hunger, that isn’t a threat. Okay, noted. Putting in the file folder for next time. And so that is a really important part to what you were talking about this a lot in our previous episode is that’s how our responses can actually shape the brain.

Dr. Greer (00:18:01):

Absolutely, absolutely. And then the other threats for babies are being alone, feeling lonely, not knowing where not being able to smell or hear or sense a caregiver, that is also perceived as a threat to them too. So sometimes they need presence, they need you there to help. So yes, and so babies wake up if they sense any of those, they’ll go through their checklist of like, am I okay? Am I feeling safe? Some especially babies with easygoing temperaments, some might not experience a lot of stress. They might wake up and you’re like, okay, everything’s fine. I’m going to rub my head and suck my thumb and go back to sleep. Babies with more sensitive stress temperaments for stress and more reactive temperaments, they’re likely going to be signaling quite a bit, right? But yes, what you said, we know when we are responsive, we are shaping their brain and we’re also giving them experiences of the association of sleep is safe when you wake up, someone’s there when you need someone, they’re there.


Nighttime’s, not a time where you’re on your own with these fears. And that gets reflected as people grow up. I wish this was studied more. I’ve been looking at it a lot lately. There are some animal studies of maternal separation that look at sleep later on, and there is at least a bit of evidence so far to show that when we are responsive to sleep in those early years, sleep does become more settled, less insomnia, more of that association of safety and sleep as we grow. So it’s also important for parents to know that as part of an informed choice, when we’re front loading the work there in those early years, we’re building that association that sleep is safe, that experience that sleep is safe, and that is likely going to lead to much more settled sleep throughout childhood when kids are able to get out of their bed and come and get you and have many, many more years of sleep. A possible sleep disturbances. Right.

Dr. Sarah (00:20:37):

Yeah, that makes a lot of sense. And even into adulthood as you’re talking, I do think it would be very interesting to see studies on how, and obviously it’d be hard, it’d be really interesting to start a longitudinal study now looking at children and then looking at adults later. Obviously if we start now, we can only just look at adults and they’re sleep training history, so that wouldn’t probably be as fruitful. But it is really interesting to look in the possible connection and relationship between sleep training. And again, we probably should define sleep training, but sleep training in infancy and early years and how an adult sleeps later. I’d just be curious.

Dr. Greer (00:21:27):

Yeah’s really, really interesting knowing now the focus on adult sleep now growing up, so many of my friends had insomnia and sleep and sleep issues and so many of us as adults do, right? Sleep is huge. We’re buying so many books.

Dr. Sarah (00:21:45):

Huge industry on adult sleep issues.

Dr. Greer (00:21:49):

Yes. And our whole generation was, many of us went through a Ferber Method of sleep training and that’s only correlation. And observation is not casual at all.

Dr. Sarah (00:22:02):

Totally. We also were those one of the first generations to deal with the internet and screens and social media and all that other stuff too. So we’d have to really be able to do a very clean study to parse that apart. But it’s a very interesting question. So you just talked about Ferber, so let’s do this. Let’s kind of name the different types of sleep training and what the different ones are. There’s quite a range.

Dr. Greer (00:22:28):

Yes, I have a list here.

Dr. Sarah (00:22:33):

So well prepared, I love it!

Dr. Greer (00:22:33):

Not the biggest stance on what it is because not only are there so many different methods of sleep training, there are also a lot of people now telling parents, this is a gentle method. There’s no crying, it’s not sleep training. And then parents buy these packages for hundreds and sometimes thousands of dollars and they are sleep training in the end. So for people who are choosing not to, it’s important for them to be informed of what it is. So the most extreme form may, I don’t know, because again, we don’t have research on this. I don’t know what’s extreme and what’s not actually, but the most kind of classic sleep training is cry out, which is like a full extinction method.

Dr. Sarah (00:23:24):

This is the Ferber method?

Dr. Greer (00:23:26):

No, it’s not Ferber, it’s pre Ferber. This started from Emmett Holt, I think in 1910, who said, put them in the room at 7:00 PM close the door and don’t come back until 7:00 AM the next morning.

Dr. Sarah (00:23:42):


Dr. Greer (00:23:43):

Yes. And this one happens the quickest. It typically happens the fastest, and it’s still really popular. Lots of people do this technique.

Dr. Sarah (00:23:55):

So am I correct? Is this informed on Skinner, Pavlov of behaviorism? Yes. Like extinction of a, so this corresponds from a timeline of the behaviorism movement. Yeah.

Dr. Greer (00:24:08):

It’s interesting though, because this was before behaviorism, right?

Dr. Sarah (00:24:12):

Yeah. When you said 1910, I was like, what? When was Skinner and Pavlov? They were after that.

Dr. Greer (00:24:17):

They were.

Dr. Sarah (00:24:18):

Okay. I just Googled it. And Pavlov actually published his first results around 1897. So actually this tracks, this is the behaviorism movement. And really fast, just in case anyone is like, what are you guys talking about? The behaviorism movement was a field of psychology research that was looking at, it was based off of the research of this psychologist Pavlov, who was looking at if you can elicit and manipulate behaviors in animals by pairing cues, stimulus cues. So basically the classic study was he would ring a bell and serve a dog food and measure the salivation of the dog. And obviously the food was eliciting the salivation, not the bell. But the more he paired the bell with the food, the more there was an association made and that he increasingly separated the time and space between the bell and the food until he extinguished the food altogether.


And the bell alone could create salivation in the dog. So this is called classical conditioning. It’s this idea that we can change a behavior based on certain stimulus in the environment. So rewards or punishments, adding a positive stimulus, removing a negative stimulus, or the punishment would be adding a negative stimulus or removing a positive stimulus. It’s very, very, sounds kind of complicated when I explain it, not that eloquent with it, but it’s relatively simple idea of the more I reward something, the more it increases. The more I punish something or make it less pleasant, the more I can decrease the behavior. That was huge in the field when it came out. It completely transformed the field of psychology at that time, and tons of offshoots of that research was then done and it’s been applied and it’s still in many ways continued to be applied to how we parent, because a lot of parenting has been focused on child’s behaviors and modifying their behaviors. And so sleep included this behavior as a model would apply to sleep. Just a quick little history of where all comes from. I actually think it’s important that we understand that piece.

Dr. Greer (00:26:48):

Yeah, it’s so important. I’m so happy you went over it. It’s also important to know and behaviorism the mind. So babies or even and parents, whoever you’re talking about, those subject’s, mind, thoughts, feelings, were a black box. We can’t know what that is. So it’s a black box, we ignore it. And so the only measure is the only thing that’s measured is behavior, not the internal experience, emotions, thoughts and conscious experiences. And so in terms of sleep training, in terms of behaviorism, it works because when we don’t respond to a baby’s cries for in this extinction method for however long the behavior of signaling for caregivers stops. So in terms of behaviorism, then it’s a success. But we’re also then not talking about any of the experiences of the baby or the parents through the process.

Dr. Sarah (00:27:58):

Or in the case of what we’re layering onto it now. The circuitry of the brain.

Dr. Greer (00:28:04):

Yeah, yeah, exactly. Exactly. So other, yeah, I think let’s go through the topics and then all the different ones, and then I’ll make a note about how sleep training actually doesn’t even produce that behaviorist working. It doesn’t actually always extinguish the cries in all babies too. And that’s another thing that parents need to know about making this informed choice that their baby might not fit into this. And that’s okay too because we know that that doesn’t happen for everyone. So then Ferber came on around in the eighties and Ferber’s method is to sort of have brief no contact checks with the babies. The first night, every five minutes parents go in, they don’t touch a baby, but they’ll say, I’m here, you can do this. And then they leave, I love you. The next day it’s every 10 minutes. The next day it’s every 15 minutes, and then so on. And I think they get larger and larger.


And that one I think is considered gentle because any of the ones where the parents go into the room are considered gentle that people would describe those as gentle sleep training. Another one is picking up and putting down. So every time the baby cries, they’re picked up and until they stop crying and then they’re put down again, and then they can cry again. And then you pick them up again and put them down again until they stop crying. Camping out or sort of gradual retreat technique is when a parent will sit next to the bed while the baby cries in a chair, and then each night the chair moves further and further away towards the door. Crying in arms is another one. This one is where parents are told to hold the baby while the baby’s crying, but to do without any act of soothing. So without rocking or feeding or singing or anything else like that. And then the last one is responsive settling, comfort settling or a soothing ladder. And this is attending when a baby cries, but with the least amount of response possible. And then you increase your response as the crying gets more intense. So first you would shush and pat the mattress.


Sometimes there’s no eye contact or they teach distinguishing between types of cries and you only respond to intense or emotional cries, but not ones that aren’t. And this one’s used a lot by sleep schools, probably the sleep schools in Australia and sometimes with the caregiver in the room or outside the room. So that kind of spans all of the techniques in terms of are the gentle ones truly more gentle than the full extinction? Unknown.

Dr. Sarah (00:31:11):


Dr. Greer (00:31:12):

And some, I mean kind of along this line, again, we have no real evidence to base it on to really just caveat that, but might the ones that are more gentle where the parent is in the room, babies cry more and they take longer. And I think it’s also a very different experience, possibly more emotionally difficult for a baby if they know you’re right there, I see you, but you’re not holding me or not soothing me or not responding to me. I don’t know. I don’t know. That’s a guess.

Dr. Sarah (00:31:53):

So we’ve described kind of a really wide range of responding to a child when they’re distressed. And I think one of the things that sticks out to me is that some of them are very responsive, but they’re very prescribed. So I think the difference perhaps between some of these very gentle parenting sleep training methods and not sleep training at all, may not actually be a huge discrepancy in the behaviors that the parent engages in. What may actually be different is what’s triggering the behavior. Is it the rule of the manualized treatment or is it the child’s cues in that moment? You actually might be doing the same thing if you’re not sleep training. It’s just kind of like when you do it. Am I getting that right?

Dr. Greer (00:32:46):

Well, I think that the responses that are prescribed in these sleep training methods, none of them allow a parent to co-regulate a child. So in all the ones that I just described, they all will. It is not allowed to take a baby, hold them until they’re not crying anymore and they’ve gone from that high state of stress to low stress and then put them down and help them fall asleep in all of them. The baby has to cry themselves to sleep essentially without any input from the parent.

Dr. Sarah (00:33:25):

Even the ones where you have to hold the baby until they stop crying and then place them back in the bed?

Dr. Greer (00:33:33):

They don’t really allow you to ever hold the baby until they’re calm.

Dr. Sarah (00:33:41):

So they’re distinguishing, crying and calm. When the cries have stopped, you set them down, but they may not be regulated. Yes. Is that the distinction?

Dr. Greer (00:33:51):

Yes. Or that’s more of a pickup put down one. And in that one the baby really just gets exhausted and passes out because they’re being picked up and put down over and over again, never getting to a place of regulation.

Dr. Sarah (00:34:06):

So then when we say not sleep training, what does that look like?

Dr. Greer (00:34:11):

Yeah, yeah, it’s important to know. So the first part are not really following schedules. Part of it using a baby’s cues, learning a baby’s cues for when they’re tired to offer naps in bedtime, and then setting up a sleep environment that is going to make your baby feel safe. And a lot of that is sharing the same room as a baby, which is called co-sleeping. And that doesn’t mean bed sharing. It means the baby’s in the same room on their own surface. That’s recommended ended, depends on the year, but for at least six months up till 12 months by many governing bodies. And they recommend that to protect babies against SIDS or sudden infant death syndrome. And the reason why it’s protective for SIDS is because when babies can hear their parents smell, their parents have all those cues from an adult that changes the quality of their sleep, they’re actually going into lighter sleep, which is actually really protective for their breathing. But the thing that happens in parallel is they’re feeling safer and that’s helping guide all of that stress circuitry to be built as well. And some babies after that six, 12 month time, if they’re in that range, that spectrum of I can sleep, I have pretty low needs for stress regulation and safety input. Sometimes they can go and sleep in their own room for part of the night or maybe a lot of the night.

Dr. Sarah (00:35:57):

So something this is also making me think about is temperament. And perhaps there’s also, I would be curious if there’s any research or data on this, but maybe the kids who have a more sensitive temperament, who have a more sensitive nervous system who do need more support at night, may also be the kids who are probably receiving more sleep training, which is a kind of tricky paradox because kids who have a more sensitive, or sorry, a more just mellow nervous system who maybe wake up and need a little less, they kind of just go back to sleep. They don’t have as much trouble with sleep, and so they’re not receiving the absence of their needs being met at night, which is almost like a self-fulfilling. It’s creates this sort of self-fulfilling problem of the easier I am, the more the environment can meet my needs without much effort by the part of the environment and the more kind of chill I am and the more safe I feel in the world.


And everything kind of is smooth sailing for me. Whereas if I’m a child who has a really sensitive nervous system who really needs a lot of support for my environment to regulate my nervous system and I’m calling out and really screaming at that environment to give me what I need, that environment is going to feel a lot more impact by me and is sometimes going to be able to meet my needs, but very often not. And so that creates a sort of also tricky sort of path that that child gets placed on of more at risk of not developing that sense of safety and that sort of safety neuro circuitry because they’re probably getting sleep trained because they’re the ones causing the ruckus at night. So yeah, it’s really tricky.

Dr. Greer (00:37:47):

Yes, some parents don’t even discover any infant sleep advice at all because their baby’s so easygoing. And then it’s the parents who have really wakeful babies who probably need lots of contact for sleep, lots of closeness, lots of help when they wake up, those are likely the parents who are going to be looking for more interventions.

Dr. Sarah (00:38:11):

And realistically, they’re the ones Googling at 3:00 AM what the hell is wrong with my kid? And what comes up when you Google it is here’s my sleep training course. Here’s this, here’s that. And so because the problem is that there’s so much noise out there with this information and then the more neuroscience informed information is not one, it’s not been around as long, it doesn’t have as much SS e o like search engine. If you Google it, that’s not going to be the first result. And so parents are just kind of this sort of biofeedback with the internet too. The more parents searching for sleep stuff, the more the sort of sleep training stuff comes up and then it kind of creates this echo chamber of sleep training information that keeps getting recycled around to parents. And it’s like this, it is a bigger issue than just, oh, I need to figure out how to spell my child sleep.

Dr. Greer (00:39:09):

I worry a lot for those babies, those really sensitive babies who are, one of the newest studies actually showed that, I don’t remember the percentage of babies, but at least some babies in the study continued to cry and signal for between 25 and 45 days in the sleep training protocol. And parents are not told maybe perhaps it’s not going to work for some babies.

Dr. Sarah (00:39:39):

They’re usually told this should work in three days or 12 weeks or whatever. What is this, 12 hours in 12 days or something? What’s that book?

Dr. Greer (00:39:48):

Yeah, 12 hours sleep by 12 weeks or something like that.

Dr. Sarah (00:39:53):

That may not be a realistic expectation for your baby, and if you don’t know that you could do some stuff that you might not otherwise choose to do.

Dr. Greer (00:40:05):

And I think that the way that it goes for those extremely sensitive babies, for the babies who feel more stressed in that place in the temperament, they’re either going to cry for those many, many days and sometimes months. I’ve been in homes where babies are crying to sleep for every nap and every night for years for the entire three years of infancy. Again, because it’s supported by the sleep training stuff that’s out there. And the other way it can go is that those babies could stop signaling really quickly of how sensitive they are. This is again, still in the world of speculation. We still need to look at this, but it is definitely a concern. Those babies, many babies, many babies I work with are needing closeness, probably sleeping in the same room for at least those first three years, sometimes, sometimes even longer, which is revolutionary.

Dr. Sarah (00:41:06):

It is. It’s counter to our culture. And I feel like that’s an important place to just sort of acknowledge that just because it’s optimal does not mean it’s possible for every family. And I think it’s important. I dunno, I’m very torn here because on the one hand I’m like, I love this idea of really being queued into your child’s cues and really tuning in and making an environment where you are optimizing for that secure attachment, but also that sort of regulation circuitry to be built. And I know too, and I think we know from attachment research that we don’t have to get it right all the time for it to work. So I wonder too though it may be optimal if it’s putting a ton of pressure on a parent to be able to meet that need, can we still give the message and would it be appropriate and accurate to say, if this isn’t where you can do it, there’s other places you can do it?

Dr. Greer (00:42:20):

I think so. It depends on the child’s needs really.

Dr. Sarah (00:42:23):


Dr. Greer (00:42:24):

It does. It really depends. It depends on, yeah, it’s really, really individualized and I think firstly for people to know that it’s really happening in almost every home that a child is really asking for help and closeness at night, and a lot of parents think that’s not expected or normal, and so they have that internal struggle with it and that can spiral them into all kinds of mental health issues too, and…

Dr. Sarah (00:42:56):

Tons of anxiety. I actually saw an article recently about is sleep training one of the biggest causes of maternal anxiety and postpartum anxiety? I’m going to find that article and put it in the show notes so people can

Dr. Greer (00:43:12):

Yeah, I would really like to see that because I see that in people I work with all the time.

Dr. Sarah (00:43:16):

And I think it’s likely a factor. I think that, so it’s such a challenging balance to strike because on the one hand, I work with a lot of parents who are at risk for perinatal mood and anxiety disorders because they may have a preexisting mental health concern. And so we’re really focused on prioritizing that parent’s sleep in the beginning because it’s a very, very protective factor for not developing a PMAD that said hyper focusing on the sleep of your child and getting really, really, really wrapped up in getting a good sleeper and moving against their biology and their intrinsic drives and creating all of this tension around sleep in the family may actually also be something that can push parents into postpartum anxiety or just any anxiety. So it’s this delicate balance of sort of, okay, yes, sleep is critical. We all need sleep to be well, our babies and us.


But perhaps as you kind of said at the beginning, maybe there are other ways to get this and maybe our society constantly telling us our kids are supposed to be good sleepers and be able to sleep so separately from us and be able to not wake through the night because that information is false. It’s just not actually based in the way the baby’s sleep cycles work or their way, their stress response system works that perhaps that’s part of the problem is us labeling something as a problem and then trying tally to fix it is what’s causing everybody so much stress. If perhaps we reframe the problem in the first place as, Hey, actually the problem might be that you have to do some things to support your child’s sleep that are counter to the way that society is telling us to. Maybe it is putting your child in your room, maybe it is getting up with them when they call for you. That’s a pretty revolutionary stance that actually is not shaming and it’s not judgy and it’s not telling parents you should just be able to do everything perfectly. Why aren’t you? It is bigger than just sleep and sleep training. I really think.

Dr. Greer (00:45:50):

Yeah, I completely agree. I have seen that in so many people that I work with. As soon as they get that information and then they can let go of that rigidity and obsession and hyper vigilance about sleep, it can overtake someone’s entire life for months, months and months. The other thing that was coming up for me when you were talking about it is the presence of the baby is regulating to the parent. And so their amygdala, the parent’s amygdala, the mom’s amygdala is going to be calmed by the presence of the baby. And that’s not going to be true for every single case. There certainly are going to be families, and I know I’ve worked with families where a baby sleeping in their own room, that is actually what’s going to bring that my mother more sleep. But in a lot of other cases, having the baby closer will you just see some people do this really intuitively. They plan to have their baby in a crib the first night on their own, and then they get into their bed and they’re like, wait, I can’t do this. And then they go sleep on the floor beside their baby’s crib. I have this drive to be close, right?

Dr. Sarah (00:47:00):

It’s helping me not feel as anxious. It’s helping me relax.

Dr. Greer (00:47:04):

And we know that anxiety and sleep are not friends.

Dr. Sarah (00:47:09):

They are very mutually exclusive because I mean, we colloquially refer to the sympathetic nervous system response is fight or flight, and it’s opposite the down regulator, the parasympathetic nervous system we refer to as rest digest. So literally in the name rest is the counterpart to the fight flight system. You can’t be both in fight or flight and rest because they are opposite ends of our nervous system activation.

Dr. Greer (00:47:43):

Yeah, yeah, absolutely. Yeah. And that’s it. It’s all, it’s going to be individualized for everyone. And I think when I work with people prenatally, they’re like, well, what sleep should I get? What sleep thing should I get? And I’m like, let’s see what kind of baby we have and then we’ll figure it out. We’ll figure it out. Do we need something smaller for the baby to sleep in your room at first and then they’ll be moved to their own or are they going to stay there? Are they going to have their own space there? Are you a candidate for bed sharing?

Dr. Sarah (00:48:17):

Can you talk a little bit about bed sharing because it’s super controversial, but I actually think that’s starting to change. There are safe ways to bed share. There are dangerous ways to bed share. And to be very clear, you need to know if you are going to do this, how to do it safely.

Dr. Greer (00:48:35):


Dr. Sarah (00:48:36):

But that’s important.

Dr. Greer (00:48:40):

Oh yeah. I always will start this conversation by saying an adult bed is not safe for a baby. You have to go through many checks and balances and set it up to be safe in order for it to be safe for a baby. And it isn’t safe for every single mom and baby or a parent and baby. That’s important to know. But we know at least 60% of Canadians and Americans admit to bringing their baby into bed and it’s way higher.

Dr. Sarah (00:49:09):

I definitely did. I was like, cannot. It was just easier every time my kid would cry, I’m tired. It was just so much easier for me to pick them up and put them next to me and feed them and go back to bed with them. And it was like I’d always start out and then by the morning they were in the bed with me. And so if you’re going to be, most people do it by default and then they don’t know how to do it safely. And so I think that is far more dangerous than us just blanketly saying never bed share.

Dr. Greer (00:49:41):

Completely. So we know that that fact is true. It is a normal human behavior, especially for breastfeeding or chest feeding moms and parents to share a surface with their baby. And most people will do it. Most people will do it. Even if I’m working with a family, they’re like, I’m never doing it. I’m like, that’s great. I love it, but let me just talk to you about how to do it safely. Because we know more likely than not, there will be at least one night, if not many nights, where it’s going to be a necessity in order for people to sleep. So most people are doing it. A lot of governing bodies have caught up to this in Canada, in the UK, the US we’re hoping is going to get on board as well. And Australia, there’s some places that are putting this information out too because we know that we can do it safely in many cases. So La Leche League is a great resource. James McKenna is a great resource. I have a bunch on my website that people can go to.

Dr. Sarah (00:50:48):

We’ll link in the show notes if you guys are interested in learning how to co-sleep safely, I will make sure to put some resources in the show notes so that you can go double check your methods, make sure it’s above board.

Dr. Greer (00:51:02):

Completely. So you want to make sure that the bed is firm. There’s no pillows or blankets near the baby. Nobody’s been smoking during pregnancy or postpartum in the house. No sedatives or alcohol are being used. And then we can kind of set ourselves up in a C, curl around baby and sleep in a very specific way. And then it works for many people. And it’s important. It’s important to know because too many people have come to me saying, we’ve been sleeping on a couch, we’ve been sleeping in an armchair because this message of no bed sharing is out there. Those are the absolute most dangerous places we never, ever, ever want a baby to be. And so learning how to set up a safe surface, it’s very, very important for families to understand.

Dr. Sarah (00:51:58):

Right? Yeah, it’s interesting. It’s like in withholding information on how to sleep safely in a bed and telling parents they’re supposed to go to their baby and get them to go back to sleep. They fall asleep in the chair in the baby’s room trying to get ’em back to bed, and that’s actually really, or on the couch, and that’s really dangerous.

Dr. Greer (00:52:18):

And I also wanted to bring up the point too, one of the other barriers we put in to deprive mothers and parents of sleep is this focus. Oh, they have to be in their own room for the whole night because then you have a parent if they’re wanting to respond, they have to wake up, walk down a hall to a baby who’s already at a high stress level, calm them down, help them get back to sleep, put them in their bed again, then go back and fall asleep. Versus if a baby is in the same room, if they’re in a cot or a bed beside the parent’s bed, maybe all they need is a hand on their chest and they’re going to fall back asleep. Maybe they need a quick feed and they’ll go back to sleep. And then that mom or parent is not even really waking up. Our sleep architecture is different when we’re sleeping close to a baby and when we’re not. And one of the most amazing things is, especially this is James McKenna‘s work and breastfeeding mothers, when a baby is about to wake up, a mother’s brainwaves will also go into a light brainwave state. And so they’re not pulled out of this very deep sleep. They’re kind of aware, they know what’s going on, they give the baby what they need, and then they easily fall back to sleep. It’s a very, very different…

Dr. Sarah (00:53:35):

That’s so interesting!

Dr. Greer (00:53:37):

Than we’re going down the hall scenario.

Dr. Sarah (00:53:39):

That’s so cool. Our brains are so cool. I just cannot handle, that’s why I like talking to you. I’m just, give me all the brain science. I think it blows my mind.

Dr. Greer (00:53:49):

It’s incredible. It’s really, really incredible how connected we can be. We are almost like one organism, brain to brain with our babies when we are close

Dr. Sarah (00:53:59):

And when we let parents have permission to stop fighting against that, a lot of this could be a little bit easier, a little bit easier.

Dr. Greer (00:54:09):

I think it’s hard for everybody no matter what, but I think when you are supporting your child’s sleep, the other parts of that are, we talked about giving them sleep opportunities when they’re tired, helping them when they wake up, helping them to fall asleep for naps in nighttime, sometimes holding them, comforting them, doing contact sleeping, which is holding them for sleep and naps. We also get more of these intensely joyful moments and moments of awe and beauty and connectedness that I think those are remembered forever. Those are the moments people want to take a time machine back to and experience again.

Dr. Sarah (00:54:59):

It’s funny you’re making me think. So I was working, I have one of my patients just had a baby. I work with a lot of perinatal and postpartum women, and really understandably, first time mom, she was feeling really upset because she’s figuring out the breastfeeding thing and it’s taking up a lot of her time. And her partner has been doing some bottle feeding. And so she’s like, basically when she’s awake, he’s feeding her and then she’s sleeping and I don’t get any time with her. And I’m like, Ugh, yeah, that’s really hard. And so she instinctively started holding the baby while the baby was sleeping because she had been taught and told, put them down when they’re sleeping. And I was like, this is perfect. This is amazing. You are getting that time with her. She doesn’t have to be awake for that. She’s getting it and you’re getting it and being able to recognize that that is enough right now and using that as your bonding time, God sitting there watching your baby sleep, that is powerful bonding time.

Dr. Greer (00:56:19):


Dr. Sarah (00:56:20):

And for your baby being held by you while they sleep is bonding for them in their unconscious sleep state so you don’t have to worry about, oh God, but they were asleep so they missed it, not based on what you’re saying, not at all. It’s still activating certain neural circuitry of safety and comfort and secure attachment even in sleep which is amazing.

Dr. Greer (00:56:42):

Oh yeah. We’re absolutely nurturing our babies in sleep. Really, really, really incredible in so many ways because in sleep, that’s where their brain is building. That’s where the circuits are building. They’re consolidating all their information and while they have, we already talked about their sleep is different when they have the safety signals of their caregivers during sleep, when they can smell, you touch you. All of these things, babies sleep longer in your arms when you’re holding them for sleep because they’re not experiencing this higher level of stress when they are sleeping alone. And it’s incredible. I mean, Nils Bergman is a researcher who talks a lot about how brain architecture is built in sleep and also advocates for baby sleeping close to caregivers for those three years while that intense brain activity is happening.

Dr. Sarah (00:57:41):

That’s so wonderful. And now obviously if you have a kid who’s zero three and you’re, again, as I promised, if you are in the right spot, you’re going to get a lot of great useful information if you have a parent, if you are a of a kid who’s older and you may be done some of these sleep training methods, I promised you I would not leave you out of this episode and not have you listening to this and end this episode feeling like, oh, man, I totally effed this up and now I have irrevocably destroyed something in my kid. That is 100% not the case. And we should probably talk a little bit about that before we end as to how can parents who are getting this information now after the fact, one, give themselves some compassion and also not feel pretty hopeful about what they could do to support their child’s brain development and sleep going forward.

Dr. Greer (00:58:33):

For sure. It depends on how you see it, what your child’s sleep is. People will be in all different situations after doing it, but really reflecting on it and I think is important and still continuing to provide that nurture for your child. However, whatever age they’re at, if they are having sleep fears, if they are not wanting to sleep alone, really you can start meeting them with their nighttime needs any time. And that can look like a lot of different ways lying with them when they fall asleep, knowing that they can come and join you in the night or have a mattress on the floor in your room, or you can come join them. I think it’s a really good idea to be leaning into those nighttime needs in childhood to start building. If there is an association between fear and bedtime and sleep, start building those safety experiences in, that’s completely fine. There’s nothing wrong with supporting a child and their sleep at any time if everything’s great and sleep is going well, continuing your nurturing and your connection during the day we know has an impact throughout childhood and throughout adolescents and further on too.

Dr. Sarah (00:59:53):

So basically what you’re saying is the brain is always constantly reaping the benefits of connection and nurturing, and that secure attachment is building and it’s constantly happening. So just redouble down now.

Dr. Greer (01:00:12):

Yeah, completely. And if you do want to have things you feel like you want to repair, you can always do that. You can always have these conversations with your child about it too.

Dr. Sarah (01:00:23):

Yeah. What might that go? What would you coach a parent on if they felt like, I want to repair some of this with you?

Dr. Greer (01:00:32):

Yeah, yeah. I mean, many people have shared stories with me that they were sleep trained and then there were also really rigid rules at night in their home. You cannot come and bother us at night for any reason, and this would be completely the status quo. This is how we’ve been approaching sleep for many, many decades. And I know for those people I know as kids, if their parents have said to them, you know what? With all the best information I had, this is how I’ve been talking to you about sleep. I’ve said, you can’t come in. I don’t want to see you at night. I’ve learned some new things and I realized that I want to make a change on that. And I realize that you might be needing me at night. You might be having fears at night, and I want you to know that you are welcome to come and join us in bed, or you are welcome to call me and I will come and help you again. I know it would make such a big difference because the stories that I’ve heard from many people are lying awake at night, terrified, unable to go to anybody for help sleeping outside their parents’ door on a hardwood floor with no pillow or blanket, just because that need was so strong to be close. And I know that that kind of repair would go so far for those kinds of situations.

Dr. Sarah (01:02:04):

And I also think if you are grappling with this and are feeling either strong feelings of guilt or not knowing how to repair or feeling that the rupture is so strong that your efforts to repair aren’t working, reach out to someone who specializes in this, and that is something that we can guide you on. You don’t have to do this all by yourself, and it can feel overwhelming, and there’s definitely support there.

Dr. Greer (01:02:33):

And if your baby’s young and you have done sleep training very often when you respond again if they’re sick or if you travel or there’s all different things that make babies signal again, especially if they’re leaving the environment that they were sleep trained in, they usually will start signaling again or if it’s responding again, and you can have a different approach if that’s your choice. Yeah.

Dr. Sarah (01:03:00):

And I think too, I also want to be really clear, if you are someone who really needs to do something, like we were talking about, if you have a mental health condition that requires sleep in a different kind of way, it’s like if you have bipolar disorder or if you have postpartum depression, these are times when sometimes you have to rank order the things, and sometimes you have to make sacrifices as one area for a higher order safety issue in another area. And it’s like sometimes these are not easy choices that we have to make, but sometimes we have to make them, and it’s kind of like a game time call or whatever that metaphor is. But I do think it’s not all or nothing. It is a nuanced decision for a lot of families, and we were speaking about there’s other ways to try to support sleep, but I think I just don’t want parents to feel like there’s only one right way. It is complicated.

Dr. Greer (01:04:09):

Yeah. It’s a risk benefit calculation, and everyone’s going to have different equations in their family.

Dr. Sarah (01:04:19):

But you guys got this. You’ve got this. Remember, we’re working with our brain and our biology in this model, which is kind of like, okay, our brains and our bodies kind of know what to do. Our intuition kind of tells us what to do if we trust it. Our child’s brain and body definitely knows what to do. We trust it. If we listen to it actually is going to be, the manual is literally in our DNA.

Dr. Greer (01:04:47):


Dr. Sarah (01:04:49):

So at least we have that going for us.

Dr. Greer (01:04:50):

No, this is brand new information coming out into the world. This is probably one of the first times I’ve talked about this in depth in public versus in my private teaching. It’s new information that we’re sharing and learning, and to also have parents know that the systems that we exist in are completely fighting against this. We’ve been set up to do sleep training as part of the systems that we live in, and it is very revolutionary. It is very, very, very different and hard to do something new. Yeah.

Dr. Sarah (01:05:28):

Yeah. All right. Well, thank you so much. This was amazing and I really appreciate it. So thank you for coming on.

Dr. Greer (01:05:38):

Thank you so much.

Dr. Sarah (01:05:45):

Thank you so much for listening. This was a tough episode for both Dr. Kirshenbaum and myself record because we were so cautious about wanting to make sure that we didn’t put pressure on parents to do or not do something, or to feel badly about something that they might’ve already done and not feel empowered. That is always what I’m trying to do with this podcast is to give parents information so that they feel empowered to make informed decisions that fit their family’s needs, and to sort of feel really confident that You are the person who gets to make these decisions. Nobody else. If you enjoyed listening to this conversation that I had with Dr. Kirshenbaum, as much as I liked recording it, and you like looking into the science behind these popular parenting trends or hearing interviews with these amazingly brilliant people who are, I’m so lucky enough to have come on this podcast and you want to help support this podcast, the best way that you can do it is to leave a review and a rating. Your comments and your ratings and your reviews are what helps us spread this message far and wide and reach the ears of other parents just like you. So I’m so grateful, and until next time, don’t be a stranger.

I want to hear from you! Send me a topic you want me to cover or a question you want answered on the show!

✨ DM me on Instagram at @securelyattachedpodcast or @drsarahbren

✨ Send an email to sarah@drsarahbren.com

✨ And check out drsarahbren.com for more parenting resources 

122. Sleep training, bed sharing, contact sleep, and postpartum: The neuroscience of sleep with Dr. Greer Kirshenbaum